CN107849006B

CN107849006B - Ethynyl derivatives

Info

Publication number: CN107849006B
Application number: CN201680027269.6A
Authority: CN
Inventors: 乔治·耶施克; 洛塔尔·林德曼; 安东尼奥·里奇; 埃里克·维埃拉
Original assignee: F Hoffmann La Roche AG
Current assignee: F Hoffmann La Roche AG
Priority date: 2015-06-03
Filing date: 2016-05-31
Publication date: 2020-11-13
Anticipated expiration: 2036-05-31
Also published as: CL2017002969A1; AR104842A1; US20210300844A1; CR20170536A; LT3303316T; CO2017012260A2; JP2018517695A; UA120309C2; HRP20200638T1; DK3303316T3; IL255367A0; EP3303316A1; PE20180358A1; CN107849006A; MA42508B1; BR112017023894A2; AU2016273751B2; PL3303316T3; KR102035048B1; TWI589571B

Abstract

The invention relates to ethynyl derivatives of formula (I), wherein R¹Is hydrogen or F; n is 1 or 2; or to pharmaceutically acceptable acid addition salts thereof. It has now surprisingly been found that the compounds of the general formula I are metabotropic glutamate receptor antagonists (negative allosteric modulators) which are useful for the treatment of anxiety and pain, depression, fragile-X syndrome, autism spectrum disorders, parkinson's disease and gastroesophageal reflux disease (GERD).

Description

Ethynyl derivatives

Technical Field

The invention relates to ethynyl derivatives of formula I

Wherein

¹R is hydrogen or F;

n is 1 or 2

Or to pharmaceutically acceptable acid addition salts thereof.

Preferred compounds are those in which (R)¹)_nIs hydrogen, 3-fluoro, 4-fluoro or 2, 5-difluoro.

It has now surprisingly been found that the compounds of general formula I are metabotropic glutamate receptor antagonists (NAM ═ negative allosteric modulators). Compounds with a similar host core have been generally described as positive allosteric modulators of the mGluR5 receptor. Surprisingly, it has been found that highly potent mGluR5 antagonists are obtained instead of mGluR5 positive allosteric modulators, which have a completely opposite pharmacology compared to positive allosteric modulators.

mGluR5 Positive Allosteric Modulators (PAM) lead to increased receptor activity (Ca) in the presence of fixed concentrations of glutamate²⁺Mobilized), and allosteric antagonists (negative allosteric modulators, NAMs) result in a reduction in receptor activation.

The compounds of formula I are distinguished by valuable therapeutic properties. They can be used for the treatment of anxiety (anxiety) and pain (pain), depression (depression), Fragile-X syndrome (Fragile-X syndrome), autism spectrum disorders (autism spectrum disorders), Parkinson's disease, and gastroesophageal reflux disease (GERD).

Background

In the Central Nervous System (CNS), the transmission of stimuli takes place through the interaction of neurotransmitters, emitted by neurons, with neuroreceptors.

Glutamate is the major excitatory neurotransmitter in the brain and has a unique role in a variety of Central Nervous System (CNS) functions. Glutamate-dependent stimulus receptors fall into two main classes. The first major class, the ionotropic receptors, form ligand-controlled ion channels. Metabotropic glutamate receptors (mGluRs) belong to the second major class and also belong to the family of G-protein coupled receptors.

Currently, eight different members of these mglurs are known, and some of these members even have subtypes. These eight receptors can be subdivided into three subgroups based on their sequence homology, signal transduction mechanisms and agonist selectivity:

mGluR1 and mGluR5 belong to group I, mGluR2 and mGluR3 belong to group II, and mGluR4, mGluR6, mGluR7 and mGluR8 belong to group III.

Negative allosteric modulators of metabotropic glutamate receptors belonging to the first group may be used for the treatment or prevention of acute and/or chronic neurological disorders, such as parkinson's disease, fragile X syndrome, autistic disorders, cognitive disorders and memory deficits (memory deficits), as well as chronic and acute pain and gastroesophageal reflux disease (GERD).

Other treatable indications in this connection are restricted brain function caused by bypass surgery or transplants, poor cerebral blood supply, spinal cord injury, head injury, hypoxia caused by pregnancy, cardiac arrest and hypoglycaemia. Further treatable indications are ischemia, Huntington's chorea, Amyotrophic Lateral Sclerosis (ALS), dementia caused by AIDS, eye injuries, retinopathy, idiopathic parkinsonism (idiophatic parkinsonism) or parkinsonism caused by drugs and conditions which lead to glutamate-deficiency functions, such as, for example, muscle spasms, convulsions (convulsions), migraine (migraines), urinary incontinence (urinary incontinence), nicotine addiction (nicotine addiction), opiate addiction (opiate addiction), anxiety (anxiety), vomiting (voicing), dyskinesia (dyskinsia) and depression.

Disorders that are wholly or partially mediated by mGluR5 are, for example, acute, traumatic and chronic degenerative processes of the nervous system, such as Alzheimer's disease, senile dementia, parkinson's disease, huntington's chorea, amyotrophic lateral sclerosis and multiple sclerosis, psychoses such as schizophrenia and anxiety, depression, pain and drug dependence (Expert opin. patents (2002), 12, (12)).

Selective mGluR5 antagonists are particularly useful in the treatment of conditions requiring reduced activation of mGluR5 receptors, such as anxiety and pain, depression, fragile-X syndrome, autism spectrum disorders, parkinson's disease, and gastroesophageal reflux disease (GERD).

Disclosure of Invention

Objects of the present invention are the compounds of formula I and pharmaceutically acceptable salts thereof, the above-mentioned compounds as pharmaceutically active substances and their preparation. Further objects of the present invention are medicaments based on the compounds according to the invention and their manufacture as well as the use of said compounds for the control or prevention of mGluR5 receptor (NAM) mediated disorders, such as anxiety and pain, depression, fragile X syndrome, autism spectrum disorders, parkinson's disease and gastroesophageal reflux disease (GERD), and respectively for the manufacture of corresponding medicaments.

The compounds of the invention have been described generally in literature 1(WO2011128279) as positive allosteric modulators of the mGluR5 receptor. The most similar exemplary compounds are attached to a 5 or 6 membered ring. Surprisingly, it has been found that compounds with a smaller ring size (4-membered ring) and with a bicyclic absolute stereochemistry (1R,5S) are highly potent mGluR5 antagonists with a completely opposite pharmacology to that described in WO2011128279 for positive allosteric modulators.

One embodiment of the invention is a compound of formula I, for example the following:

(1S,5R) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0] heptan-3-one

(1R,5S) -2- (5- ((4-fluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one

(1R,5S) -2- (5- ((3-fluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one or

(1R,5S) -2- (5- ((2, 5-difluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one.

Drawings

The main difference between positive and negative allosteric modulators can be seen in fig. 1. mGluR5 Positive Allosteric Modulators (PAM) lead to increased receptor activity (Ca) in the presence of a fixed concentration of glutamate²⁺Mobilized), and allosteric antagonists (negative allosteric modulators, NAMs) result in a reduction in receptor activation. The receptor affinity in FIG. 1 for PAM is about 10^-7M, and for NAM is at 10^-7M and 10^-8M is greater than or equal to the total weight of the composition. These values can also be measured using a binding assay instead of radioligand (═ MPEP), see assay description.

FIG. 1 shows a schematic view of a: comparison of mGluR5 Positive Allosteric Modulators (PAM) and mGluR5 antagonists (negative allosteric modulators ═ NAM)

The indications that can be addressed by the compounds are different. mGluR5-NAM is beneficial for indications that require a reduction in excess receptor activity, such as anxiety, pain, fragile X chromosome, autism spectrum disorders, and gastroesophageal reflux disease. mGluR5 PAM, on the other hand, may be used in indications where normalization of reduced receptor activity is required, such as psychosis, epilepsy, schizophrenia, alzheimer's disease and related cognitive disorders, and tuberous sclerosis.

This difference can be shown in practice in an animal model of anxiety, such as the Vogel Water conflict test in rats, where the compound of example 1 shows anxiolytic activity at a minimum effective dose of 0.1mg/Kg, whereas mGluR-PAM is not considered to show activity in this animal model (see FIG. 2).

FIG. 2: compound "example 2" activity in rat Vogel conflict drinking water assay.

Detailed Description

Biological assays and data:

²⁺intracellular Ca mobilization assay

Generating a monoclonal HEK-293 cell line stably transfected with cDNA encoding the human mGlu5a receptor; for work with mGlu5a Positive Allosteric Modulators (PAMs), cell lines with low receptor expression levels and low constitutive receptor activity were selected to allow differentiation of agonist activity from PAM activity. Cells were cultured according to standard protocols (Freshney, 2000) in high glucose Dulbecco's Modified Eagle Medium supplemented with 1mM glutamine, 10% (vol/vol) heat inactivated calf serum, penicillin/streptomycin, 50 μ g/ml hygromycin and 15 μ g/ml blasticidin (all cell culture reagents and antibiotics from Invitrogen, basel, switzerland).

About 24 hours before the experiment, 5x10⁴Individual cells/well were seeded in poly-D-lysine coated 96-well plates with black/clear bottom. Cells were loaded with 2.5. mu.M Fluo-4AM in loading buffer (1xHBSS, 20mM HEPES) for 1 hour at 37 ℃ and washed five times with loading buffer. The cells were transferred to a Functional Drug Screening System 7000 (Hamamatsu, Paris, France) and assayed at 37 deg.C11 semilog serial dilutions of the compound and cells were incubated for 10-30 minutes and fluorescence recorded online. After this pre-incubation step, the cells are added with EC₂₀Agonist L-glutamate at the corresponding concentration (typically about 80 μ M) and fluorescence is recorded online; to account for the day-to-day variation in cellular responsiveness, the EC of glutamate was determined by recording the full dose response curve of glutamate immediately prior to each experiment₂₀。

The response was measured as the peak increase in fluorescence minus baseline (i.e., fluorescence without addition of L-glutamic acid), normalized to the maximum stimulatory effect obtained with saturating concentrations of L-glutamic acid. Plot with% maximal stimulation using XLfit, a curve fitting program that iteratively plots the data using the Levenburg Marquardt algorithm. The single site competition assay equation used was y ═ a + ((B-a)/(1+ ((x/C) D))), where y is% maximal stimulatory effect, a is minimal y, B is maximal y, and C is EC₅₀X is the log10 of the concentration of the competing compound, and D is the slope of the curve (Hill Coefficient). From these curves, EC was calculated₅₀(concentration that achieves half maximal stimulation), hill coefficient, and maximal response expressed as% of the maximal stimulatory effect obtained with the saturating concentration of L-glutamic acid.

During preincubation with PAM test Compounds (i.e., during application of EC)₂₀Prior to the concentration of L-glutamate) indicates agonist activity, and the absence of this signal indicates lack of agonist activity. In the addition of EC₂₀A decrease in the signal observed after the concentration of L-glutamic acid is indicative of the inhibitory activity of the test compound.

All shown in the list of the following examples have an EC of less than or equal to 100nM₅₀Corresponding results for compounds of value.

WO 2011128279-document 1

MPEP binding assay:

for binding experiments, human mGl was encodedcDNA for the u5a receptor Using Schlaeger and Christensen [ Cytotechnology 15:1-13(1998)]The described procedure was transiently transfected into EBNA cells. Cell membrane homogenates were stored at-80 ℃ until days were assayed, at which time they were thawed and resuspended and homogenized (polytronised) in 15mM Tris-HCl, 120mM NaCl, 100mM KCl, 25mM CaCl at pH 7.4₂、25mM MgCl₂Binding buffer to 20 u g protein/hole final assay concentration.

By subjecting twelve 2 [ deg. ] C to a treatment at 4 [ ]³H]The saturation isotherm was determined by adding MPEP concentrations (0.04-100nM) to these membranes (in a total volume of 200. mu.l) for 1 h. Using a fixed concentration of³H]A competition experiment was performed in MPEP (2nM) and the IC of the test compound was evaluated using 11 concentrations (0.3-10000nM)₅₀The value is obtained. Incubation was performed at 4 ℃ for 1 h.

At the end of the incubation, the membranes were filtered on a unifilter with Filtermate 96 collector (Packard BioScience) (96-well white microplate with GF/C filter bound, preincubated for 1h in 0.1% PEI in wash buffer, Packard BioScience, Meriden, CT) and washed 3 times with cold 50mM Tris-HCl (pH 7.4 buffer). Nonspecific binding was measured in the presence of 10 μ M MPEP. After addition of 45 μ l microscint 40(Canberra Packard S.A., Zurich, Switzerland) and shaking for 20min, radioactivity on the filters was counted on a Packard Top-count microplate scintillation counter with quenching correction (3 min).

Shown in the list of the following examples are ECs having less than or equal to 20nM₅₀Corresponding results for compounds of value.

Comparison of compounds of the present invention with the most similar compounds described in WO2011128279 examples 106 and 109:

as can be seen in the table below, the compounds of the invention show a significantly different pattern (profile) compared to structurally similar compounds of the prior art, which is an advantage when compounds showing NAM activity are desired.

The compounds of formula I can be prepared by the methods given below, by the methods given in the examples, or by analogous methods. Suitable reaction conditions for the individual reaction steps are known to the person skilled in the art. The reaction sequence is not limited to the sequence shown in the scheme, but the sequence of the reaction steps may be freely changed depending on the starting materials and their respective reactivities. The starting materials are commercially available or can be prepared by methods analogous to those given below, by the methods described in the literature or in the examples cited in the description, or by methods known in the art.

The compounds of formula I of the present invention and their pharmaceutically acceptable salts can be prepared by methods known in the art, for example, by the process variants described below, which comprise

Reacting a compound of formula II

Wherein X is a halogen atom selected from bromine or iodine

With a suitable aryl-acetylene of the formula III

To form a compound of formula I

Wherein the substituent R¹Described hereinabove in enantiomerically pure form having the absolute stereochemistry shown in formula I, or by using the racemic form of II followed by chiral separation of I to give optically pure enantiomersA body; and is

If desired, the compound obtained is converted into a pharmaceutically acceptable acid addition salt.

The preparation of the compounds of formula I is also described in more detail in schemes 1 to 3 and examples 1-4.

Scheme 1

The synthesis of compounds of formula IIa is depicted in scheme 1. Halo-pyridine compounds of formula IIa can be obtained by palladium catalyzed reaction of the appropriate dihalopyridine, such as 2-bromo-5-iodo-pyridine, with the appropriately substituted cyclic urea of formula 5 (scheme 1). Reaction of 2-chloro-or 2-fluoro-pyridines having bromine or iodine in the 5-position with bicyclic ureas of formula 5 can also form compounds of formula IIa by aromatic nucleophilic substitution reactions using basic conditions such as, for example, NaH/THF or cesium carbonate/DMF. The compound of formula 5 may be obtained starting from an appropriately protected 2-amino-1-carboxylic acid of formula 1, which may be obtained using a procedure similar to that described in Gorrea & al, Tetrahedron asymmetry,21,339 (2010). The acid function of 1 is converted via an acyl azide intermediate to the corresponding isocyanate 2(Curtius rearrangement), which then cyclizes to form the bicyclic urea compound 3. The free NH group of 3 can be alkylated according to standard procedures to form compound 4, which is then deprotected to give cyclic urea 5. Optically pure intermediates 2 to 5 can also be obtained starting from optically pure protected acids of formula 1 or by isolating the racemic mixture at any stage of the synthesis using procedures known to those skilled in the art.

Scheme 2

Wherein R in this scheme¹Means quilt (R)¹)_nA substituted phenyl group.

A compound of formula IIa (X ═ B)R, I) can be reacted with a suitable aryl-acetylene of formula III (wherein W is hydrogen or an in situ cleavable protecting group such as trialkylsilyl-or aryldialkylsilyl, preferably hydrogen or trimethylsilyl) under palladium catalyzed coupling conditions (Sonogashira reaction) to form a compound of formula Ia wherein substituent R is¹As described above. Another possibility includes reacting IIa with trimethylsilylacetylene to give a compound of formula Ia, where R is¹Is trimethylsilyl and then subjected to a second Sonogashira reaction with the appropriate aryl bromide or aryl iodide to give the compound of formula I (scheme not shown).

In the case of amino acid derivative 1 in racemic form, the enantiomers can be separated at any given stage during the synthesis of the compound of formula I using procedures known to those skilled in the art.

The order of the reactions to produce the compounds of formula I can also be reversed (scheme 3). In this case, the Sonogashira reaction between arylacetylene derivative III and dihalo-pyridine is first carried out to give arylacetylene-pyridine compound of formula 6, which is then condensed with bicyclic urea 1 to give compound of formula I.

Scheme 3

Wherein R in this scheme¹Means quilt (R)¹)_nA substituted phenyl group.

The pharmaceutically acceptable salts of the compounds of formula I can be prepared easily according to methods known per se and taking into account the nature of the compound to be converted into a salt. Inorganic or organic acids such as, for example, hydrochloric, hydrobromic, sulfuric, nitric, phosphoric or citric acid, formic, fumaric, maleic, acetic, succinic, tartaric, methanesulfonic, p-toluenesulfonic acid and the like are suitable for forming pharmaceutically acceptable salts of basic compounds of formula I. Compounds comprising an alkali or alkaline earth metal (e.g., sodium, potassium, calcium, magnesium, etc.), a basic amine, or a basic amino acid are suitable for forming pharmaceutically acceptable salts of acidic compounds.

As mentioned and mentioned above, the compounds of formula I and their pharmaceutically acceptable salts are metabotropic glutamate receptor antagonists and can be used for the treatment or prevention of mGluR5 receptor mediated disorders, such as acute and/or chronic neurological disorders, cognitive disorders and memory deficits, as well as acute and chronic pain. Treatable neurological disorders are, for example, epilepsy, schizophrenia, anxiety disorders, acute, traumatic and chronic degenerative processes of the nervous system, such as alzheimer's disease, senile dementia, huntington's chorea, ALS, multiple sclerosis, dementia caused by AIDS, eye injuries, retinopathy, idiopathic parkinson's disease or parkinson's disease caused by drugs and conditions which lead to glutamate-deficiency functions, such as, for example, muscle spasms, convulsions, migraine, urinary incontinence, nicotine addiction, psychosis, opiate addiction, anxiety, vomiting, dyskinesia and depression. Other treatable indications are restricted brain function caused by bypass surgery or grafts, poor cerebral blood supply, spinal cord injury, head injury, hypoxia caused by pregnancy, cardiac arrest and hypoglycaemia.

The compounds of formula I and their pharmaceutically acceptable salts are particularly useful as analgesics. The types of pain that can be treated include inflammatory pain such as arthritis and rheumatoid diseases, vasculitis, neuropathic pain such as trigeminal or herpetic neuralgia, diabetic neuropathy pain, causalgia, hyperalgesia, severe chronic pain, post-operative pain and pain associated with various conditions such as cancer, angina, renal or biliary colic, menstruation, migraine and gout.

The pharmacological activity of the compounds was tested using the following method:

cDNA encoding rat mGlu5a receptor was transiently transfected into EBNA cells using the procedure described in e. [ Ca ]²⁺]i measurements were performed on mGlu5a transfected EBNA cells after incubation with Fluo 3-AM (obtained from FLUKA, 0.5. mu.M final concentration) for 1 hour at 37 ℃ and washing 4 times with assay buffer (DMEM supplemented with Hank's salt and 20mM HEPES). [ Ca ]²⁺]i measurements were performed using a fluorescence imaging plate reader (FLIPR, M)olecular Devices Corporation, La Jolla, CA, USA). When compounds were evaluated as antagonists, they were tested against 10 μ M glutamate as antagonist.

Inhibition (antagonist) curves were fitted using the iterative nonlinear curve fitting Software Origin (Microcal Software inc., north ampton, MA, USA) using the four parameter logistic equation (logistic equation) to give IC₅₀And hill coefficient.

The Ki values for the tested compounds are given. The Ki value is defined by the formula:

wherein the IC₅₀Values are the concentration of the tested compound in μ M that antagonizes 50% of the compound's effect. [ L ]]Is the concentration and EC₅₀Values are the concentration of the tested compound in μ M that produced 50% stimulation.

The compounds of the invention are mGluR 5a receptor antagonists. The activity of the compound of formula I measured in the above assay is at K_i<In the range of 100. mu.M.

The compounds of formula I and their pharmaceutically acceptable salts can be used as medicaments, for example in the form of pharmaceutical preparations. The pharmaceutical preparations can be administered orally, for example, in the form of tablets, coated tablets, dragees, hard and soft gelatine capsules, solutions, emulsions or suspensions. However, the administration can also be effected rectally, for example in the form of suppositories, or parenterally, for example in the form of injection solutions.

The compounds of formula I and their pharmaceutically acceptable salts can be processed with pharmaceutically inert, inorganic or organic carriers for the preparation of pharmaceutical preparations. Lactose, corn starch or derivatives thereof, talc, stearic acid or its salts and the like can be used, for example, as such carriers for tablets, coated tablets, dragees and hard gelatine capsules. Suitable carriers for soft gelatine capsules are, for example, vegetable oils, waxes, fats, semi-solid and liquid polyols and the like; depending on the nature of the active substance, however, no carriers are generally required in the case of soft gelatin capsules. Suitable carriers for the preparation of solutions and syrups are, for example, water, polyols, sucrose, invert sugar, glucose and the like. Adjuvants, such as alcohols, polyols, glycerol, vegetable oils and the like, may be used in the aqueous injection solutions of the water-soluble salts of the compounds of formula I, but in general this is not essential. Suitable carriers for suppositories are, for example, natural or hardened oils, waxes, fats, semi-liquid or liquid polyols and the like.

In addition, the pharmaceutical preparations can contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They may also contain additional other therapeutically valuable substances.

As mentioned before, medicaments containing a compound of formula I or a pharmaceutically acceptable salt thereof and a therapeutically inert excipient are also an object of the present invention, as are processes for the preparation of such medicaments, which processes comprise: one or more compounds of formula I or a pharmaceutically acceptable salt thereof and, if desired, one or more other therapeutically valuable substances are brought into a galenical form together with one or more therapeutically inert carriers.

The dosage can vary within wide limits and will of course be adapted to the individual requirements in each particular case. In general, an effective dose for oral or parenteral administration is between 0.01 and 10 mg/kg/day, with 0.1 to 5 mg/kg/day being preferred for all the indications described. The daily dose for an adult human weighing 70kg is accordingly between 0.7 and 700 mg/day, preferably between 7 and 350 mg/day.

The following examples are provided to further illustrate the invention:

example 1

(-) - (1S,5R) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0] heptan-3-one

Step 1: (rac) - (1SR,2RS) -2- (naphthalen-2-ylmethoxycarbonylamino) cyclobutanecarboxylic acid methyl ester：

To a well stirred solution of (rac) - (cis) - (1RS,2SR) -cyclobutane-1, 2-dicarboxylic acid monomethyl ester (CAS: 31420-52-7) (10.8g, 68.3mmol) and N-methylmorpholine (7.6g, 8.26ml, 75.1mmol) in 160ml of 1, 2-dichloroethane was added diphenylphosphoryl azide (20.7g, 16.2ml, 75.1mmol) dropwise. After stirring at room temperature for 10min, the reaction was warmed to 60 ℃. 2-Naphthylmethanol (10.8g, 68.3mmol) and copper (I) chloride (68mg, 0.68mmol) were added and the reaction was stirred at 60 ℃ for a further 16 h. The reaction was concentrated in vacuo, the light brown oily residue (51g) was diluted with 15ml dichloromethane and purified by flash chromatography on silica gel (SiO)₂(650g) Ethyl acetate/heptane 20:80) to yield 16.8g of impure material containing unreacted naphthyl methanol. The material was repurified (aminohaze, 0% to 35%, ethyl acetate gradient in heptane) to give 11.1g (52%) of the title compound as a white crystalline solid, MS: 314.2(M + H)⁺)。

Step 2: (rac) - (1SR,2RS) -2- (naphthalen-2-ylmethoxycarbonylamino) cyclobutanecarboxylic acid

To a well stirred solution of methyl (rac) - (1SR,2RS) -2- (naphthalen-2-ylmethoxycarbonylamino) cyclobutanecarboxylate (example 1, step 1) (4.2g, 13.4mmol) in 20ml dioxane was added water (70 ml). The solution was cooled to 5 ℃ and 53.6ml (26.8mmol) of 0.5M sodium hydroxide solution were added dropwise over a period of 5 min. After stirring for 1h at 5 ℃, the reaction was warmed to room temperature with vigorous stirring. The clear solution was then cooled to 5 ℃ and the pH was adjusted to 2.5 by adding about 13ml of 2N hydrochloric acid solution. The reaction was separated and purified with ethyl acetate. After drying, filtration and concentration in vacuo, 3.87g (97%) of the title compound was obtained as a crystalline white solid, MS: 300.2(M + H) M/e⁺)。

And step 3: (rac) - (1RS,5SR) -3-oxo-2, 4-diaza-bicyclo [3.2.0]Heptane-2-carboxylic acid naphthalene- 2-Ylmethyl ester

(rac) - (1SR,2RS) -2- (naphthalen-2-ylmethoxycarbonylamino) cyclobutanecarboxylic acid (example 1, step 2) (2.34g, 7.82mmol) and N-methylA solution of morpholine (0.79g, 0.86ml, 7.82mmol) in 34ml of dichloroethane was stirred at room temperature for 10 min. Diphenylphosphorylazide (2.15g, 1.69ml, 7.82mmol) was then added dropwise at room temperature and the colorless solution was stirred at room temperature for 1h, during which time the solution became light yellow. The solution was then warmed to 50 ℃, stirred for 6h, and cooled. After purification with dichloromethane/water separation, the combined organic phases were evaporated to dryness to give a yellow solid which was recrystallized from ethyl acetate/heptane. The title compound (1.86g, 80%) was obtained as a white crystalline solid, MS: m/e 297.3(M + H)⁺)。

And 4, step 4: (rac) - (1RS,5SR) -4-methyl-3-oxo-2, 4-diaza-bicyclo [3.2.0]Heptane-2- Naphthalen-2-ylmethyl formate

To (rac) - (1RS,5SR) -3-oxo-2, 4-diaza-bicyclo [3.2.0]To a solution of heptane-2-carboxylic acid naphthalen-2-ylmethyl ester (example 1, step 3) (1.13g, 3.81mmol) in 11ml of DMF was added a 60% suspension of sodium hydride in mineral oil (0.198g, 4.96 mmol). The suspension was stirred at room temperature for 35 minutes (gas evolution), then iodomethane (0.81g, 0.36ml, 5.72mmol) was added and the mixture was stirred at room temperature overnight. After quenching by addition of 3ml of saturated ammonium chloride solution and concentration in vacuo, the residue was purified by separation of ethyl acetate/water. To be combinedOrganic phaseDried and concentrated in vacuo. The residue was purified by flash chromatography on silica gel (50g) eluting with a gradient of 20-100% ethyl acetate in heptane to give 0.98g (82%) of a colourless oil, MS: 311.2(M + H) M/e⁺)。

And 5: (rac) - (1SR,5RS) -2-methyl-2, 4-diaza-bicyclo [3.2.0]Hept-3-ones

A solution of (rac) - (1RS,5SR) -4-methyl-3-oxo-2, 4-diaza-bicyclo [3.2.0] heptane-2-carboxylic acid naphthalen-2-ylmethyl ester (example 1, step 4) (0.97g, 3.13mmol) in 15ml methanol was hydrogenated over 10% Pd/C (0.333g, 0.313mmol) for 48 h. The solution was purged with argon, the catalyst was filtered off and washed with ethyl acetate. The filtrate was concentrated in vacuo. The residue was purified by flash chromatography on silica gel (20g) eluting with a gradient of 50-100% ethyl acetate in heptane to yield 0.375g (95%) of the title compound as a crystalline white solid which was used directly in the next step without further characterization.

Step 6: (rac) - (1RS,5SR) -2- (5-iodo-pyridin-2-yl) -4-methyl-2, 4-diaza-bicyclo [3.2.0]Hept-3-ones

To (rac) - (1SR,5RS) -2-methyl-2, 4-diaza-bicyclo [3.2.0]Heptan-3-one (example 1, step 5) (375mg, 2.97mmol) and 2-fluoro-5-iodopyridine (683mg, 3.06mmol) in DMF (10ml) was added to a 60% suspension of sodium hydride in mineral oil (155mg, 3.86 mmol). The reaction was stirred at rt overnight. After removal of DMF by quenching with addition of 3ml saturated ammonium chloride solution and concentration in vacuo, the residue was purified by separation of ethyl acetate/water. After drying and concentration in vacuo, the residue was subjected to flash chromatography (SiO) using an ethyl acetate gradient from 0% to 65% in heptane₂20g) purification. The title compound (549mg, 56%) was obtained as a crystalline white solid, MS: 330.1(M + H) M/e⁺)。

And 7: (rac) - (+/-) - (1SR,5RS) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0]Hept-3-ones

In a 5ml microwave tube, 110mg (0.33mmol) of (rac) - (1RS,5SR) -2- (5-iodo-pyridin-2-yl) -4-methyl-2, 4-diaza-bicyclo [3.2.0]Hept-3-one (example 1, step 6) was dissolved in 1.5ml DMF. Argon gas was bubbled through the solution. Ethynylbenzene (73. mu.l, 68mg, 0.67mmol), bis (triphenylphosphine) palladium (II) chloride (14mg, 20. mu. mol), copper (I) iodide (1.9mg, 10.0. mu. mol), triphenylphosphine (1.8mg, 7.7. mu. mol) and107mu.l triethylamine (101mg, 140. mu.l, 1.0 mmol). The dark brown solution was stirred at 60 ℃ for 3 h. The reaction was purified with ethyl acetate/water separation, dried and concentrated in vacuo. The residue was purified by flash chromatography (silica gel, 20g, 0% to 50%, EtOAc in heptane gradient) to yield 95mg (94%) of the title compound as a light brown crystalline solid, MS: 304.2 (m/e) ((m/e))M+H⁺)。

And 8: (-) - (1S,5R) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0]Hept-3-one and (+) - (1R,5S) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0]Hept-3-ones

Coupling (rac) - (+/-) - (1SR,5RS) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0]Racemic mixture of heptan-3-one (example 1, step 7) (95mg) by chiral HPLC: (Chiralpak)

-5cmx50cm, 20 mM; 40% isopropanol/heptane, 35ml/min, 18 bar). Peak detection is achieved using a UV detector and an Optical Rotation Detector (ORD), where one peak has a negative signal ((-) -enantiomer) and the other peak has a positive signal ((+) -enantiomer). The (-) -enantiomer, namely (-) - (1S,5R) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0 is obtained]Hept-3-one (39mg) as a crystalline pale yellow solid, MS: 304.1(M + H) M/e⁺). The (+) -enantiomer, i.e., (+) - (1R,5S) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0]Hept-3-one (40mg) as a pale yellow solid, MS: 304.1(M + H) M/e⁺)。

Example 2

(-) - (1R,5S) -2- [5- (3-fluoro-phenylethynyl) -pyridin-2-yl ] -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one

The title compound was prepared according to the general method of example 1, step 7 by: from (rac) - (1RS,5SR) -2- (5-iodo-pyridin-2-yl) -4-methyl-2, 4-diaza-bicyclo [3.2.0]Hept-3-one (example 1, step 6) (110mg) and 1-ethynyl-3-fluorobenzene were started to give 107mg (96%) of the racemic material ((+/-) - (1R,5S) -2- [5- (3-fluoro-phenylethynyl) -pyridin-2-yl]-4-Methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow crystalline solid; MS: 322.3(M + H) M/e⁺) This was then separated by chiral HPLC using similar separation conditions as described in example 1, step 8, to give enantiomerically pure (-) - (1R,5S) -2- [5- (3-fluoro-phenylethynyl) -pyridin-2-yl]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow solid, MS: 322.3(M + H) M/e⁺) (ii) a And enantiomer (+) - (1S,5R) -2- [5- (3-fluoro-phenylethynyl) -pyridin-2-yl thereof]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow solid; MS: 322.3(M + H) M/e⁺)。

Example 3

(-) - (1R,5S) -2- [5- (4-fluoro-phenylethynyl) -pyridin-2-yl ] -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one

The title compound was prepared according to the general method of example 1, step 7 by: from (rac) - (1RS,5SR) -2- (5-iodo-pyridin-2-yl) -4-methyl-2, 4-diaza-bicyclo [3.2.0]Hept-3-one (example 1, step 6) (110mg) and 1-ethynyl-4-fluorobenzene were started to give 104mg (97%) of the racemic material ((+/-) - (rac) - (1SR,5RS) -2- [5- (4-fluoro-phenylethynyl) -pyridin-2-yl]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow crystalline solid; MS: 322.3(M + H) M/e⁺) This was then separated by chiral HPLC using similar separation conditions as described in example 1, step 8, to give enantiomerically pure (-) - (1R,5S) -2- [5- (4-fluoro-phenylethynyl) -pyridin-2-yl]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow solid, MS: 322.3(M + H) M/e⁺) (ii) a And enantiomer (+) - (1S,5R) -2- [5- (4-fluoro-phenylethynyl) -pyridin-2-yl thereof]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow solid; MS: 322.3(M + H) M/e⁺)。

Example 4

(-) - (1R,5S) -2- [5- (2, 5-difluoro-phenylethynyl) -pyridin-2-yl ] -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one

The title compound was prepared according to the general method of example 1, step 7 by: from (rac) - (1RS,5SR) -2- (5-iodo-pyridin-2-yl) -4-methyl-2, 4-diaza-bicyclo [3.2.0]Hept-3-one (example 1, step 6) (110mg) and 2-ethynyl-1, 4-difluorobenzene gave 110mg (97%) of the racemic material ((+/-) - (rac) - (1SR,5RS) -2- [5- (2, 5-difluoro-phenylethynyl) -pyridin-2-yl]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow crystalline solid; MS: 340.1(M + H) M/e⁺) This was then separated by chiral HPLC using similar separation conditions as described in example 1, step 8, to give enantiomerically pure (-) - (1R,5S) -2- [5- (2, 5-difluoro-phenyl-ethynyl) -pyridin-2-yl]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow solid, MS: 340.1(M + H) M/e⁺) (ii) a And enantiomer (+) - (1S,5R) -2- [5- (2, 5-difluoro-phenyl-ethynyl) -pyridin-2-yl thereof]-4-methyl-2, 4-diazabicyclo [3.2.0]Hept-3-one as a pale yellow solid; MS: 340.1(M + H) M/e⁺)。

Preparation of the pharmaceutical composition:

example I

Tablets having the following composition were prepared in a conventional manner:

example II

example III

Capsules having the following composition were prepared:

the active ingredient, crystalline lactose and microcrystalline cellulose having a suitable particle size are homogeneously mixed with one another, sieved and then mixed with talc and magnesium stearate. The final mixture is filled into hard gelatin capsules of suitable size.

Claims

1. A compound of the formula I, wherein,

wherein

R¹Is hydrogen or F;

n is 1 or 2

Or a pharmaceutically acceptable acid addition salt thereof.

2. A compound of formula I according to claim 1, which is

(1S,5R) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0] heptan-3-one;

(1R,5S) -2- (5- ((4-fluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one;

(1R,5S) -2- (5- ((3-fluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one; or

3. A process for the preparation of a compound of formula I according to any one of claims 1 or 2, comprising the steps of:

reacting a compound of formula II

Wherein X is a halogen atom selected from bromine or iodine,

with aryl-acetylenes of the formula III

To form a compound of formula I

Wherein the substituent R¹As described above, in enantiomerically pure form with the absolute stereochemistry shown in formula I, or by using the racemic form of II followed by chiral separation of I to give an optically pure enantiomer, wherein W is hydrogen or an in situ cleavable trialkylsilyl or aryldialkylsilyl group; and is

4. A pharmaceutical composition comprising a compound according to any one of claims 1 or 2 and a therapeutically active carrier.

5. The use of a compound as claimed in any one of claims 1 or 2 for the preparation of medicaments for the treatment of anxiety and pain, depression, parkinson's disease and gastroesophageal reflux disease.

6. A compound selected from:

(+) - (1R,5S) -2-methyl-4- (5- (phenylethynyl) pyridin-2-yl) -2, 4-diazabicyclo [3.2.0] heptan-3-one;

(+) - (1S,5R) -2- (5- ((3-fluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one;

(+) - (1S,5R) -2- (5- ((4-fluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one; or

(+) - (1S,5R) -2- (5- ((2, 5-difluorophenyl) ethynyl) pyridin-2-yl) -4-methyl-2, 4-diazabicyclo [3.2.0] heptan-3-one.